So-called “network switches” are used to route both signaling and data traffic through a network. These switches are sometimes exposed to sustained periods of high traffic. When the traffic volume is very high, a network switch is “overloaded”. Arriving “service request messages” will experience high delays and arbitrary “throttling, resulting in reduced throughput. When a switch becomes overloaded the end customers of a service provider (e.g., telephone company) usually see the effect because the service they expect is adversely affected.
The challenge, therefore, is to develop techniques for minimizing or controlling switch “overloads”. In particular, within each switch there are one or more processors (collectively referred to as “processor”) that may become overloaded. It is essential that techniques be developed which respond to, and quickly eliminate overloads that may occur.
Existing techniques are available to control processor overloads. One such technique is referred to as Occupancy. Generally speaking, this technique requires the calculation of “occupancy” values in order to determine how “occupied” a processor is at a given interval of time. Depending on the calculated occupancy values, an overload condition is determined to exist or not. If one exists, steps are taken to reduce the overload condition. However, Occupancy-based techniques have their disadvantages. First, calculating occupancy values is easier said than done. Second, Occupancy-based techniques are slow in responding to sudden overload conditions. Third, existing occupancy techniques are subject to recurring overloads because, once an overload condition is removed, they allow too much traffic to build up too quickly. This is also true for other existing overload control techniques not just Occupancy-based techniques. What is needed is a more controlled return of traffic when overload conditions are substantially eliminated or cease.
Accordingly, it is desirable to provide easy-to-implement techniques that provide for the elimination of overload conditions and a controlled return of traffic after such conditions are substantially eliminated.